Question

When I submit this url:

http://localhost:3333/User/GetAll?_dc=1345288777353&page=1&start=1&limit=25&callback=Ext.data.JsonP.callback2 

The controller won’t deserialize PagingModel page. The debugger shows that page = null.

public class PagingModel
{

    public string start { get { return _start; } set { _start = value; } }
    private string _start;

}

public class UserController : Controller
{

    [HttpGet]
    public JsonResult GetAll(PagingModel page)
    {
           ///////////////////
           //page is null.
           ///////////////////
    }
}

Answer 1

Oops, rename your action parameter:

[HttpGet]
public JsonResult GetAll(PagingModel model)
{
   ///////////////////
   // model is no longer null
   ///////////////////
}

The reason for that is because you already have a page=1 query string parameter in your request making the default model binder go berserk who is trying to deserialize the value 1 to PagingModel which obviously is hard to happen.